Disperant concentrate based on degradation products of polysaccharides in the dyeing of textiles

ABSTRACT

A liquid dispersant concentrate stable against clouding at a temperature of 10° C. to 35° C. containing: (a) from 20% to 50% by weight of the degradation products of polysaccharides containing uronic acid units; and (b) the remainder, water, all weights being based on the weight of the concentrate.

This application is a 371 of PCT/EP94/03124 filed Sep. 19, 1994.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a liquid dispersant concentrate based ondegradation products of polysaccharides containing uronic acid unitswhich is stable against clouding at normal temperature.

2. Discussion of Related Art

Nowadays, dispersants are often used in the finishing of textiles, forexample in pretreatment or in dyeing. Examples of such dispersants arelignin sulfonates, reaction products of lignin sulfonic acid with alkylhalides or alkyl sulfonic acid chlorides, protein fatty acidcondensates, naphthalene sulfonic acid/formaldehyde condensates,alkylaryl sulfonates, polyvinyl alcohols, polyvinyl pyrrolidone,polyacrylates, glucose-containing polyacrylate copolymers,polyphosphates and derivatives thereof (cf. for example UllmannsEncyklopadie der technischen Chemie, Volume A8, pages 586-590).

Unfortunately, the commercially available dispersants presently used bythe expert for the finishing of textiles are attended by thedisadvantage that they are either based on petrochemical raw materialsand/or show poor biological degradability or eliminatability. Inaddition, many dispersants are powders which are more difficult to usein measured quantities by comparison with liquids.

DESCRIPTION OF THE INVENTION

The problem addressed by the present invention was to provideecologically safe liquid dispersant concentrates based on native rawmaterials which would be suitable above all for use in the finishing oftextiles. In particular, the dispersant concentrates according to theinvention would avoid the above-described disadvantages of the priorart. A dispersant concentrate is understood to be a formulation whichcontains the dispersant in aqueous medium in a quantity of at least 20%by weight.

It has now surprisingly been found that the degradation products ofpolysaccharides containing uronic acid units effectively meet therequirements stated above in every respect.

Accordingly, the present invention relates to a liquid dispersantconcentrate containing degradation products of polysaccharides and waterwhich is stable against clouding at normal temperature, the degradationproducts being obtainable by thermal, hydrolytic, oxidative or enzymaticdegradation of polysaccharides containing uronic acid units and

the degradation products being present in a quantity of 20 to 50% byweight, based on the concentrate as a whole, and

the viscosity of the dispersant concentrate--as measured at 20° C. witha Brookfield viscosimeter (spindle 1)--being in the range from 10 to 500mPa.s.

Normal temperature in the context of the present invention is understoodto be a temperature in the range from 10° to 35° C.

In the context of the invention, uronic acid units are understood on theone hand to be the uronic acids themselves, for example D-glucuronicacid or D-galacturonic acid, and on the other hand salts or estersthereof where a corresponding modification of the free carboxyl group ofthe uronic acids is present in the naturally occurring raw material. Forexample, it is known that the carboxyl group of glucuronic acid isusually present in the form of its Ca or Mg salt in vegetable gums andmucilages (cf. for example Henseke G., "Zuckerchemie" Berlin 1966, page136). Examples of uronic acid units in which the carboxyl group ispresent in the form of its ester are pectin and tragacanth which containinter alia D-galacturonic acid methyl esters as principal units.

Polysaccharides containing uronic acid units are naturally occurringproducts. They may be unconditionally used for the production of thedegradation products to be employed in accordance with the invention.The type and quantity of uronic acid units present in thepolysaccharides are basically not critical. For example, pectin whichoccurs in the cell walls and middle lamellae of higher terrestrialplants contains the uronic acid units D-galacturonic acid andD-galacturonic acid methyl ester as principal constituents. Algin whichoccurs in the cell walls of brown algae contains the uronic acid unitsD-mannuronic acid, L-guluronic acid and the corresponding acetylderivatives as principal constituents.

Gum arabic (acacia gum) is mentioned as an example of a polysaccharidewhich does not consist solely or substantially of uronic acid units.This gum is the dried plant exudate which is obtained from the trunk orbranches of various acacia species. The exudate also forms in the eventof natural damage to the bark. For commercial production, cuts are madein the trees and the drops forming are collected after drying in air.Gum arabic is made up of the units L-arabinose, D-galactose, L-rhamnoseand D-glucguonic acid in a ratio of about 3:3:1:1. However, thiscomposition varies according to the acacia species, the time of year andthe location.

Among the polysaccharides containing uronic acid units, those selectedfrom the group consisting of pectin, algin, gum arabic, tragacanth,karaya gum, ghatti gum, shiraz gum and xanthan are particularlypreferred.

In one particularly preferred embodiment, polysaccharides containinguronic acid units emanating from exudates of plants, including inparticular gum arabic, tragacanth, karaya gum, ghatti gum and shirazgum, are preferred.

It is specifically pointed out that cellulose and starch are not countedamong the polysaccharides to be used for degradation in accordance withthe invention because they do not contain any uronic acid units.

In the context of the invention, degradation products of polysaccharidescontaining uronic acid units are understood to be products which areobtainable by thermal, hydrolytic, oxidative or enzymatic degradation ofthe polysaccharides mentioned and which have a lower average molecularweight than the polysaccharides used for degradation and a higheraverage molecular weight than the monomer units--the products ofcomplete degradation.

The polysaccharides used for degradation are of native origin.Accordingly, the molecular weights of the polysaccharides are subject tocertain variations according to the particular regional and climaticconditions.

According to the invention, degradation of the polysaccharides iscarried out in aqueous medium in such a way that a viscosity of 10 to500 mPa.s, as measured at 20° C. with a Brookfield viscosimeter (spindle1), is established for a solids content of 20 to 50% by weight. In otherwords, the viscosity of the polysaccharides functionally describes theirdegree of degradation.

The dispersing effect of the concentrates according to the invention isof the same order of magnitude as that of relevant commercialconcentrates known to the expert from the prior art. In addition, theconcentrates according to the invention have the further advantage thatthe degradation products of polysaccharides containing uronic acid unitspresent in them are readily biodegradable and show very goodeliminatability by comparison with comparable known dispersants for thefinishing of textiles.

The concentrates according to the invention are preferably adjusted to apH value in the range from 5.0 to 9.0 and, more particularly, to a pHvalue in the range from 6.5 to 7.5.

In one special embodiment of the present invention, the degradation ofthe polysaccharides containing uronic acid units is carried out in thepresence of acids. The dispersant concentrates produced in this way havethe additional advantage of improved stability in storage. This meansthat the dispersions are stable against clouding, i.e. do not show anysigns of separation or creaming, even after storage for several months.It also means that there is hardly any change in consistency, i.e. theviscosity of the concentrates remains substantially constant in storage.

The type of acid used for the degradation of the polysaccharides isbasically not critical. Examples of suitable acids are hydrohalic acids,such as HCl, sulfuric acid, phosphoric acid, polyphosphoric acid,amidosulfonic acids, lactic acid, glycolic acid, citric acid, tartaricacid. Acids particularly preferred for degradation are sulfuric acid,amidosulfonic acid and citric acid.

The degradation of shiraz gum with citric acid, particulars of which canbe found in the Examples of the present application, is cited at thisjuncture as a representative example of the production of the dispersantconcentrates according to the invention. However, the degradation of thepolysaccharides suitable for the purposes of the invention is notconfined to the particular conditions disclosed in the Examples. Thus,there are no particular limits to the reaction temperature and reactiontime or to the type and quantity of reagent optionally used fordegradation (acid, base, oxidizing agent, enzyme) in the degradation ofthe polysaccharide. In addition, degradation may be carried outcontinuously or discontinuously. Degradation is typically carried out byinitially introducing the polysaccharide to be degraded in aqueousmedium in a quantity of around 20 to 65% by weight and continuing thedegradation process until the reaction mixture has reached the requiredviscosity. The reaction mixture is then filtered, optionally afteradjustment to the required pH value, the filtrate obtained being theliquid dispersant concentrate according to the invention stable againstclouding at normal temperature which contains the polysaccharidedegradation products in a quantity of 20 to 50% by weight, based on theconcentrate as a whole, and which has a viscosity in the critical rangefrom 10 to 500 mPa.s, as measured at 20° C. with a Brookfieldviscosimeter (spindle 1).

As already mentioned, the degradation products of polysaccharidescontaining uronic acid units should be present in the concentratesaccording to the invention in a quantity of 20 to 50% by weight, basedon the concentrate as a whole, and the viscosity should be adjusted to avalue of 10 to 500 mPa.s, as measured at 20° C. with a Brookfieldviscosimeter (spindle 1). The following preferred ranges are mentionedin this connection:

for the content of degradation product in the concentrate: 30 to 40% byweight

for the viscosity of the concentrate: 10 to 100 mPa.s.

In another embodiment of the present invention, the dispersantconcentrates contain one or more other dispersing substances asadditional constituents in addition to the degradation products ofpolysaccharides containing uronic acid units. The additional dispersingsubstances should be present in quantities of 0.1 to 10.0% by weight,based on the concentrate as a whole. Combinations of the above-describeddegradation products of polysaccharides containing uronic acid unitswith polyvinyl pyrrolidone have proved to be particularly effective.

The dispersant concentrates according to the invention may be used withadvantage in the finishing of textiles.

Accordingly, the present invention also relates to the use of a liquiddispersant concentrate stable against clouding at normal temperaturewhich contains degradation products of polysaccharides obtainable bythermal, hydrolytic, oxidative or enzymatic degradation ofpolysaccharides containing uronic acid units and also water, thedegradation products being present in a quantity of 20 to 50% by weight,based on the concentrate as a whole, and the viscosity of the dispersantconcentrate, as measured at 20° C. with a Brookfield viscosimeter(spindle 1), being in the range from 10 to 500 mPa.s in the finishing oftextiles, more particularly for dispersing pigment soil in thepretreatment of textiles and for dispersing dyes in the dyeing oftextiles.

The following Examples are intended to illustrate the invention withoutlimiting it in any way.

EXAMPLES

1. General

1.1. Substances used

Dispersants

D-l: Commercial lignin sulfonate, solids content: 30% by weight

D-2: Commercially available powder-form naphthalene sulfonicacid/formaldehyde condensate

D-3: Commercially available liquid, water-free glucose-containingpolyacrylate copolymer.

b) Dyes

Indanthrene blue: "Indanthrenblau RS" (a product of BASF)

Palanil marine blue: "Palanilmarineblau BGF" (a product of BASF)

c) Other substances

Hydrosulfite: Sodium dithionite, Na₂ S₂ O₄ (a product of BASF)

1.2. Dilutions

In the testing of the dispersing effect, dilutions are mentioned in thefollowing formulations. Thus:

a) The expression "1:10 solution" for the dispersant means that thecommercially obtainable dispersant or the particular dispersant producedin accordance with Example 1 is further diluted with water in a ratio of1:10 from the particular concentration present. The solution obtainedwas used in a quantity of 2.0 g/l for the formulation.

b) The expression "1:100 solution" for the dye means that thecommercially obtainable solid dye is diluted with water in a ratio of1:100. The dispersion obtained is used in a quantity of 0.1 g/l for theformulation.

2. Preparation and characterization of the dispersant concentrates

Example 1

5 kg of water were introduced into an autoclave and first 50 g of citricacid and then 3.7 kg of shiraz gum were added at room temperature. Themixture was heated to 135° C. under an excess pressure of 1.5 bar andtreated for 150 minutes at that temperature. After cooling to roomtemperature, the mixture was neutralized with sodium hydroxide and,finally, was filtered through a pressure filter.

The following characteristic data were determined:

pH value (100 g product H₂ O): 7.0

Dry matter content: 31.2% by weight

Viscosity: 22 mPa.s (20° C., Brookfield viscosimeter, spindle 1).

3. Testing of the dispersing effect

3.1. For the dye Indanthrenblau

Formulation: 2.0 g/l dispersant (1:10 solution)

0.1 g/l Indanthrenblau RS (1:100 solution)

10.0 ml/l sodium hydroxide 38° Be

2.0 g/1 Hydrosulfite

Procedure

800 ml of water (8° dH) were introduced into a glass beaker and theformulation constituents mentioned above were added in the orderindicated. The liquor was thoroughly mixed and heated to 55° C. on a hotplate. After a treatment time of 20 minutes, 2.0 ml/l of hydrogenperoxide (50%) were added. After another 5 minutes, 12 ml/l of aceticacid (60%) were added. The treatment was continued for another 5 minutesbefore the liquor was filtered under suction through a filter nutscheprovided with a paper filter and connected to a water jet pump.

Evaluation

The appearance of the paper filter was evaluated by a trained test panelof three people with experience in the field of textile dispersants andcorresponding performance evaluation. The evaluation was based on ascale of 1 (poor) to 6 (very good).

The extreme points of the scale may be described as follows:

If the filter is only light blue in color and if the holes of the filternutsche beneath the filter shimmer through only weakly, a score of 6 isawarded. If the filter is coated with a color lake and the holes of thenutsche beneath the filter are clearly visible with a coarse structure,a score of 1 is awarded. Accordingly, a score of 6 indicates excellentdispersing power (little dye remaining on the filter) while a score of 1expresses poor dispersing power (numerous dye particles remaining on thefilter).

The following results were obtained according to the particulardispersant used:

    ______________________________________                                        Dispersant           Evaluation                                               ______________________________________                                        Degradation product of shiraz gum                                                                  4                                                        (according to Example 1)                                                      D-1                  3-4                                                      D-2                  3-4                                                      D-3                  1-2                                                      ______________________________________                                    

3.2. For the dye Palanilmarineblau

Formulation: 2.0 g/l dispersant (1:10 solution)

0.1 g/l Palanilmarineblau RS (1:100 solution)

2.0 ml/l 60% acetic acid

Procedure

The formulation constituents mentioned above were introduced into 400 mlof water (8° dH) in the order indicated. The liquor as a whole wasintroduced into a stainless steel container suitable for a "Labomat"laboratory dyeing machine (Werner Mathis AG, Zurich). In the Labomat,the liquor was heated to 125° C. at a rate of 2° C./minute and was keptat that temperature for 1 hour. After cooling to 60° C., the liquor wasfiltered under suction through a filter nutsche as described under 3.1.

Evaluation

Evaluation was carried out as described in 3.1.

The following results were obtained according to the particulardispersant:

    ______________________________________                                        Dispersant           Evaluation                                               ______________________________________                                        Degradation product of shiraz gum                                                                  5                                                        (according to Example 1)                                                      D-1                  5                                                        D-2                  5                                                        D-3                  1-2                                                      ______________________________________                                    

We claim:
 1. A liquid dispersant concentrate stable against clouding ata temperature of from 10° C. to 35° C. comprising:(a) from 20% to 50% byweight of the degradation products of polysaccharides containing uronicacid units; (b) from 0.1% to 10% by weight of polyvinyl pyrrolidone; and(c) the remainder, water, all weights being based on the weight of theconcentrate, said dispersant concentrate having a viscosity from 10 to500 mPa.s as measured at 20° C. with a Brookfield viscosimeter spindleno.
 1. 2. A concentrate as in claim 1 wherein said degradation productsare derived from polysaccharides selected from the group consisting ofpectin, algin, gum arabic, tragacanth, karaya gum, ghatti gum, shirazgum and xanthan.
 3. A concentrate as in claim 1 wherein said degradationproducts are derived from plant exudates selected from the groupconsisting of gum arabic, tragacanth, karaya gum, ghatti gum and shirazgum.
 4. A concentrate as in claim 1 having a pH value from 5.0 to 9.0.5. A concentrate as in claim 1 wherein said degradation products areformed in the presence of an acid.
 6. A concentrate as in claim 5wherein said acid is selected from the group consisting of hydrohalicacid, sulfuric acid, phosphoric acid, amido-sulfonic acid, lactic acid,glycolic acid, citric acid, tartaric acid and mixtures thereof.
 7. Aconcentrate as in claim 1 wherein said degradation products are obtainedby thermal degradation, hydrolytic degradation, oxidative degradation,or enzymatic degradation.
 8. The process of dispersing a textile finishcomposition comprising combining said textile finish composition with aliquid dispersant concentrate which is stable against clouding at atemperature of from 10° C. to 35° C., said concentrate comprising:(a)from 20% to 50% by weight of the degradation products of polysaccharidescontaining uronic acid units; (b) from 0.1% to 10% by weight ofpolyvinyl pyrrolidone; and (c) the remainder, water, all weights beingbased on the weight of said concentrate, said concentrate having aviscosity from 10 to 500 mPa.s as measured at 20° C. with a Broodeldviscosimeter spindle no.
 1. 9. A process as in claim 8 wherein saiddegradation products are derived from polysaccharides selected from thegroup consisting of pectin, algin, gum arabic, tragacanth, karaya gum,ghatti gum, shiraz gum and xanthan.
 10. A process as in claim 8 whereinsaid degradation products are derived from plant exudates selected fromthe group consisting of gum arabic, tragacanth, karaya gum, ghatti gumand shiraz gum.
 11. A process as in claim 8 wherein said concentrate hasa pH value from 5.0 to 9.0.
 12. A process as in claim 8 wherein saiddegradation products are formed in the presence of an acid.
 13. Aprocess as in claim 12 wherein said acid is selected from the groupconsisting of hydrohalic acid, sulfuric acid, phosphoric acid,amido-sulfonic acid, lactic acid, glycolic acid, citric acid, tartaricacid and mixtures thereof.
 14. A process as in claim 8 wherein saiddegradation products are obtained by thermal degradation, hydrolyticdegradation, oxidative degradation, or enzymatic degradation.
 15. Aprocess as in claim 8 wherein said textile finish composition contains adye.
 16. A process as in claim 15 further including contacting a textilematerial with said textile finish composition.